Tap.



T. F. KHAN.

TAP.

APPLICATION FILED MAILQ, 1912.

' 1,080,980, Patented Dec.9, 1913.

2 SHEETS-SHEET 1; 5

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' 8 1% M if coLu/num PLANuunm-il cu. WASHINGTON. u. c.

T. F. KEAN.

TAP.

APPLICATION FILED MAR. 9, 1912.

Patented Dec. 9, 1913.

2 SHEETSSHEET 2.

CDLUMBIA PLANCIGRAPH co, WASHINU'IION,

UNITED PTT @FFTC.

THOMAS F. KEAN, or BOSTON, MAs'sAonusnTTs, ASSIGNQROF oivn rinnr ToILLTAM A. MACLEOD AND ELDON MACLEOD, or WESTWOQD, u ssAoHUsnTT's, ANDCHARLES w. MGGONNEL, or BOSTON, MAssAorfUsnTTs, TRUSTEES.

TAP.

Specification of LettersPatent.

Patented'Dec. 9, 1913.

Application filed narch'ejieia serial naesajros.

To all whom'z'zf ma concern.-

Be it known that I, THOMAS F. KEAN, a citizen of the United States,residing at Boston, county of Suflolk, State of Massachusetts, haveinvented a certain new and useful Improvement in Taps, of which thefollowing is a specification, reference being had therein to theaccompanying drawings.

My invention has for its object an improvement in automatic taps of thetype in which the cutters are automatically withdrawn from engagementwith the threads when a predetermined point has been reached so that thework may thereafter be drawn back from the tap without rotating eithertap or work.

deretofore, so far as is known to me, it has been customary to constructdevices of this character in such a manner that the automatic latch bymeans of which the cutters are disengaged from the threads is operatedwhen the face of the nut or other piece of work which is next to the tapcontacts with the trigger of the latch.

The device embodying my present invention is so constructed that thetrigger contacts with the bottom of the hole to be tapped instead of theface of the nut or other article and therefore the tap may be stoppedwith great accuracy at any predetermined distance from the bottom of thehole, thereby making it possible to tap thin or irregular pieces ofwork.

The tap embodying my present invention is also constructed so as to bevery efficient and durable and the cutters are readily movable butwithout lost motion, while at the same time they are supported in asolid block of metal so that the device has the rigidity of a solid tap.A convenient means of adjustment for depth of hole is also provided aswell as means whereby the position of the cutters may be changed asrequired to compensate for wear.

The invention will be fully understood from the following descriptiontaken in connection with the accompanying drawings, and the novelfeatures thereof will be pointed out and clearly defined in the claimsat the close of the specification.

In the drawings, Figure l is a top plan View of a device embodying mypresent invention some portions being broken away to; illustrate thedevice more clearly. Fig. 2 1s asideelevat'ion of a tap embodying myinvention, some of the parts being also broken away. Fig. 3 is a sectionon line 3'-8 of Fig. 1 looking in the direction of the arrow. Fig. 4.-is a section of the block or body in which the cutters are supportedbeing taken on line 4-i Fig. 2 looking in the direction of the arrows.Fig. 5 is a side view of one cutter. Fig. 6 is a side view of one wedge,being one which operates the cutter shown in Fig. 5. Fig. 7 is a sectionon line 7-7 Fig. 5. Fig. 8 is a section on line 8-8 Fig. 6.

Referring now to the drawings: At A is shown the arbor which is placedin the turret-head. At B is shown the body or block of the t'ap withinwhich are received the four cutters C. To the arbor A is rigidlyfastened a collar D by means of a set-screw 11. The arbor A, the body B,the collar D are all rigidly connected and therefore are stationaryrelatively to each other. The cutters C are 'sli'dable radially in thebody B and are moved by Wedges 15 secured to a head 12 which is slidableon the arbor A, being moved in one direction by means of the rotatablecam 13, and in the other direction by the springs 14.

The slots 16 in the body B containing the wedges 15 and cutters C areT-shaped in cross-section as will be plainly seen from Fig. 4, toreceive two longitudinal ribs 17 and 18 on the said wedges. The cuttersG are connected with the wedges 15 by means of a rib 19 on the cutterwhich interlocks with a groove 20 on the wedge, and a rib 21 on thewedge which interlocks with the groove 22 on the cutter. As the twomembers are confined in the groove 16 in the block B, the cutter C issecured firmly in place in the block B and may be moved in eitherdirection by the wedge 15, this movement being a positive one in bothdirections owing to the interlocking connection between the cutter andthe wedge. This construction is also such that the cutters cannot becomedisplaced or drop out. The cutters C are themselves guided radially bymeans of two slots 23 and 24 one in eachside of each cutter, these slotsbeing engaged by the edges of an adjacent pair of segmental plates 25secured to the block B by the screws 26. As the wedges 15 and thecutters C are both wedge shaped as shown in Figs. 5 and 6, it will beseen that a longitudinal movement of the wedges, 6. parallel with theaxis of the arbor will move the cutters radially but the cutters willnot be moved longitudinally. The four wedges 15 are rigidly secured tothe head 12 by means of four screws 27, there being interposed betweenthe wedge and the head 12 a sleeve or thimble 28. K

The cam 13 is cut with two cam faces 29 and 30 and is secured to thecollar although rotatable relatively to it, by two semi-circular plates31, 32, which are screwed to the cam 13. The cam is provided with ahandle 321 by means of which it is rotated. Two wedge-shaped fixed camfollowers 33 and 34 are secured to the head 12 and are held in contactwith the cam faces 29 and 30 by the springs 14, one end of each of whichbears against the lower face of the head 12 while the other end rests onthe body B. "When the cam 13 is rotated about sixty degrees by means ofthe handle 321, the head 12 and the wedges 15 secured thereto are movedto the left as shown in Fig. 1, thereby moving the cutters G intooperative position. The parts are secured in this position by means of alatch stud 341 secured to the block 13. The latch stud 341 is providedwith an annular groove 35 which is engaged by a latch 36 which isslidable in a hole in the head 12. The latch 36 is pressed against thelatch stud 341 by the spring 37, the tension of which is adjusted by thescrew 38. WVhen the cam 13 is rotated by the handle 321, the head ismoved to the left and the latch 36 slides on the latch stud until itsnaps into the groove 35. Thereafter the parts remain in this positionwith the springs 14 compressed and the cutters C in operative positionuntil the latch is released. The releasing mechanism for the latchcomprises a trigger 39 which passes through a hole in the block B andprotrudes beyond the end of the tap, in such a position that it willcontact with the bottom of the hole in the work which is being tappedwhenever the tap has gone the predetermined distance. This trigger 39 isprovided at its upper end with an inclined surface a engaging acorresponding inclined surface I) formed in a slot 0 in the latch 36.When the trigger 39 contacts with the bottom of the hole, the furtheradvance of the tap presses back the trigger 39 and moves the latch 36 byreason of the action of the inclined faces a and b releasing the latchfrom the latch stud 341 and allowing the head to snap back under thepressure of the springs '14. This movement of the head withdraws thecutters from the threads so that the tap and the work may then beseparated without rotating either piece. The trigger 39 is held fromrotating which would result in disengagement of the inclined faces a andb by means of a pin 40 passing through a thimble 41 on the lower side ofthe head 12 and engaging a slot 42in the trigger 39.

The trigger 39 is made in two pieces the lower of which is designated45, the two pieces being screwed together. When it is desired to carrythe threads nearer to the bottom of the hole the piece 45 is unscrewedand a shorter one is substituted. If the tap stops too near the bottom,a longer piece is put on. This forms a provision for adjustment fordepth of hole.

The adjustment to vary the amount which the cutters protrude beyond thesurface of the block is accomplished by changing the position of thelatch stud 341. As the cut ters wear, the stud is screwed farther intothe block, so that the head 12 moves farther to the left as seen in Fig.1 before the latch engages the stud.

What I claim is 1. In a tap, the combination of an arbor, a body havingradial slots therein T-shape in cross section, metal plates on said bodyforming corresponding slots between their adjacent edges, wedges T-shapein cross section movable longitudinally of said slots and interlockingcutters having slots therein engaging the sides of the slots in saidplate and movable radially therein, and a rotatable cam on said arborfor actuating said wedges.

2. In a tap, the combination of an arbor, a body, cutters in the saidbody movable radially, wedges moving the said cutters radially bymovement longitudinally of the arbor, a head secured to said wedges andslidable longitudinally of the arbor, a rotatable cam moving said headin one direction, a spring moving the said head in the other direction,and a latch.

3. In a tap, the combination of an arbor, a body, cutters in the saidbody movable radially, wedges moving the said cutters radially bymovement longitudinally of the arbor, a head secured to said wedges andslidable longitudinally of the arbor, a rotatable cam moving said headin one direction and a spring moving the said head in the otherdirection, a latch to secure the head in operative position, a triggerpassing through said body and engaging said latch.

4. In a tap, the combination with a body having a T-shaped slot therein,cutters in the said slot, radially movable wedges having ribs engagingthe groove forming parts of said T-shaped slot, said cutters and saidwedges being interlocked by means of corresponding grooves and ribs.

5. In a tap, the combination of a body, radially movable cutterscontained in slots in the said body, moving means to operatethe saidcutters, a head to which the said moving' means are secured, springsmoving said In testimony whereof I afiix my signa- %ea% in olnedilrectign, a cam moving Sablld ture, in presence of two Witnesses.

ea in t e 0t1er irection, an a justa e latch stud, a latch on said headto engage THOMAS KEAN' said latch stud and a trigger passing throughWitnesses:

said body to disengage the latch from the JOHN H. PARKER,

said latch stud and release the head. ALICE H. MORRISON.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. 0.

